Tolmie john tresidder



(No Model.)

T. J. TRESIDDER.

MANUPACTURB 0F ARMOR. PLATES. No. 475,864. Patented May 24, 1892.

NITED STATES ,TOLMIE JOHN TRESIDDER,

OF SHEFFIELD, ENGLAND.

MANUFACTU RE OF ARMOR-PLATES.

SPECIFICATION forming part of Letters Patent No. 475,364, dated May 24, 1892.

Application filed September 8, 1891. Serial No. 405 ,097. (No model.) Patented in France September 3, 1891, No. 215,886, and in Italy September 30, 1891, No. 30,334.

To all whom it may concern-.-

Be it known that I, TOLMIE JOHN Tansin- DER, a subject of the Queen of Great Britain, now residing at the Atlas Steel Works, Sheffield, in the county of York, England, have invented certain new and useful Improvements in the Manufacture of Armor-Plates, (for which I have obtained the following patents, viz: French Patent No. 215,886, dated September 3, 1891, and Italian Patent No. 30,334, dated September 30, 1891,) of which the following is a specification.

When a water bath is employed in hardening pieces of steel in large bulk unsatisfactory results are obtained mainly on account of the formation of a steam envelope around the immersed article, which envelope being continually broken and reformed during the early stages of quenching only allows the heat to be abstracted spasmodically instead of with the uniformity which is the first requisite for a successful result. The superior action of an oil bath is due not to the chemical composition of oil, but to the absence of the steam envelope. Vhere glycerine or any substance tending to raise the boiling-point is added to a water bath, the result is improved for a similar reason. 4

According to my present invention I manufacture armor-plates, giving to them the requisite shape, strength, hardness, and tenacity by a process which does away with the formation of a steam-envelope.

According to my invention I may use water or similar chilling fluid without encountering the objectionable features above referred to'. I preferably use water; but I do not limit myself to the use of water alone, as my process has the contingent advantage of allowing any fluid, gas, or vapor to be uniformly applied to one side only of an armor-plate or similar article, which would not be possible by immersion in a bath unless the surface to be treated happened to be perfectly flat.

It is Well known that in the manufacture of armor-plates serious difficulties have been encountered owing to the warping of the plate by the hardening or tempering process, which distorts it from the desired shape or designers templet. Vhen armor-plates are thus warped or distorted, it is very difficult to get them into "proper shape; but according to my process vuse apparatus such as shown in the accompanying drawings, in which- Figure 1 is a plan View of a douche or spraying apparatus which I may employ. Fig. 2 is a side View of my apparatus for use on a plate intended to be finished flat or slightly curved. Fig. 3 is a side view of a modification thereof in use with a plate of considerable curvature. Fig. t shows a guard to prevent the too-rapid cooling of the corners of plates. Fig. 5 is a guard of different form to protect the edges. Fig. 6 shows a perspective view of a portion of a plate provided with corner and edge protecting guards. Fig. 7 is a section of a portion of the end of the plate. Fig. 8 is a section of a perforated water-pipe.

Referring now to the details of my drawings by letters, a ct a a (see Fig. 1) are fourinch quarter-bends with Hanges.

b is a four-inch straight pipe.

c is a four-inch pipe with two four-inch connections d CZ fromvthe water-service. To the pipes b c are connected two four-inch pipes e e, cast with numerous teats for one-inch screw connections, in which are screwed a series of one-inch cross-pipes fff, having the long unions g g. These pipes are full of oneeighth-inch perforations on the under side, drilled at various angles to spread the jets of water. Douches of different sizes should be provided-some flat, as above, and others more or less curved.

b2 is an armor-plate, bent concave to finish fiat.

In Fig. 2, a2 a2 is the douche above described. c2 c2 c2 is a tray adapted to hold water up against the back of the plates. d2 d2 are cast-iron pyramids on which the plate rests. e2 e2 indicate water overflowing the edges of the tray and running to waste. X is one of the waterinlets.

In Fig. 3, a3 d3 is the upper douche for hardening a curved plate. b3 b3 is the lower douche for moderating the warp, and c3 c3 c3 c3 are the water-inlets, both douches being substantially like that shown in Fig. 1, but

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curved to suit the curved armor-plate, (indicated by d3 d3.) e3 e3 are the keyways in edges temporarily filled up. The full line shows the curve of the false templet and the dotted line that of the designers templet.

This will be straight or curved, as required,

The upper flange rests on the top of the plate and the clamping-screws bite on the under surface.

By my process, as will be further explained hereinafter, I obtain, first, intense hardness and tenacity in the faces of compound armorplates; (steel faced with iron backs;) second,v intense hardness and tenacity in the faces of compound steel armor-plates, (all steel with or without nickel, the., with high carbon faces and mild backs, whether built up or made originally homogeneous and subsequently converted on one side,) and, third,increased tenacity and toughness, such :as has hitherto been obtained by oil-hardening followed by annealing in homogeneous steel armorplates, whether containing chrome, nickel, or other such ingredients or not. The injurious and commonly fatal internal strains induced in a large mass of steel by quenching it in a water bath are entirely avoided by my process, which at the same time retains all the valuable properties inherent to waterquenching. i

Before describing my method of using the apparatus I will state that repeated experiments have shown me that the warping produced by quenching a straight plate nine or ten inches thick from one side only is of a uniform convexity toward the quenched side, and that the amount of convexity is about three-eighths of an inch in a distance of four feet; also, thatthewarpingof asteel-faced compound plate of the same thickness quenched from both sides is similar in nature, but` less in extent, being at the rate of about one-fourth of an inch in a distance of four feet. Homogeneous steel plates equally quenched from both` sides after being uniformly heated have no tendencyto warp. Experiment has also shown me that by bending'a fiat plate till it is con-` cave on the side to be hardened to an extent determined in the manner above specified, its

ilatness will be restored by the warp due to quenching. Thus plates to be treated by this process must be originally bent with less convexity on the hard side than ultimately required, and to do this properly Iprovide false templets, to which the plates areA yto be bent. The proper form for these false templets can be arrived at approximately by applying one of the corrections given above and with accuracy after a few trials with the particular kind of plate to be treated. Thinner plates warp more than thicker ones. A plate four inches thick shows a convexity of One-half an inch in four feet when hardened on one side only. This being understood, I will proceed to describe my processfof treating various plates. as follows:

First. If the plate be treated is a compound plate (steel face and iron back) to finish approximatelyviiat, (as belt-plates,) I make it and machine it in the usual way, except that I use false tem plets to which to bend it.' These false templets are constructed from the designers templets. When the plate is Iinished as far as regards all machine-work to the steel portion, all holes (if there be any such, as those tapped in the top edges of beltfplates for the deck attachment) in the steel are plugged with flush wrought-iron screw-plugs arranged soA as to be withdrawn with facility. Similarly, any keyways in the edges, if in the steel portion, are fitted with temporary keys k. The plate b2 is then carefully heated in a furnace to a hardening heat, which will of course vary with the nature of the steel, ordinarily a moderate red heat will suffice. When hot enough, it is taken from the furnace and deposited steel side up on four supports d2 in a large flat tray c2 (see Fig. 2) in such a way that the edge of the tray is everywhere a little higher than the bottom of the plate. The douche a2 is then brought up and supported a little above the plate, and the water, which is preferably at a high pressure-say eighty pounds to the square inch-is turned on. Atiirstthe waterquenchesthe steel side only; but in a few moments the tray becomes full and forms a bath for the lower iron side. The object of this is to reduce the warping of the plate, which it does by about one-half. It also tends to assist the'chilling action of t-he douche above, but the soft iron on which it acts is not affected. It the ut- `most possible degree of hardness is desired,

the douching is continued t-ill the plate is cold; but I 4sometimes stop the water after all redness has disappeared, throw on the plate some scraps of soft alloy, and turn on the wateragan as soon as these scraps show signs of melting. In this way by using alloys of suitable melting-points the plate can be tempered with great nicety to any required degree. When the plate is cold,it will be found to have its proper finished shape if the false templets have been correctly made and worked to. The temporary plugs and keys (if. any) can be withdrawn and the bolt-holes drilled and tapped in the back to complete the plate. No correction whatever of the edges should be required; but if it proves necessary itwillbe so smallas to be readily corrected by grinding with an emery-wheel. In order to prevent too great rapidity of cooling at the corners of the plate, I sometimes IOO IIO

attach thereto iron shoes, Fig. 4, which modifyv extent of keepingthem soft enough to be ma.

chined.

Second. If the plate to be hardened is a compound plate (steel face and iron back) to be finished with considerable curvature, (as a turret or conning-tower plate,) I proceed exactly as described above, except that instead of a tray I use a second douehing apparatus to cool the under side of the plate, Fig. 3. This acts upward; butit must be rememberedin all cases that the douche which is to harden the plate is at its best advantage when acting directly downward. In the full lines show the curve of the metal before hardening, While the dotted lines show the curve when the plate is cooled.

Third. If the plate to be treated is a compound steel plate in which the back is of so mild a nature as to undergo water-quenching Without losing toughness, the double douche, as described, for a curved compound plate may be used; but if it is undesirable to quench the back, then the downward douche on the face only, without any tray to hold the water up against the back, is to be preferred. In some cases I use the double douche with water above the plate and air or wet air below.

Fourth. If the plate to be treated is a homogeneous steel plate requiring toughness throughout rather than a hard face, either the double douche or the single douche with tray will be efficient. In a case of this kind I prefer to use a double douche of wet air applied in the same way as the water.

As regards the water-pressure to be used I prefer a high pressure-say eighty pounds to the square inch; but this depends greatly upon the area of the surface to be treated. In any case there must be sufficient volume of water to cause a brisk flow from all the apertures of the douching apparatus. For the air or wet-air quenching a pressure of about ten pounds to the inch will suffice.

In cases Where it is not desirable to let the Water run to waste, orwhere the douching apparatus is employed with specialfluids which are of value, arrangements can easily be made for catching the fluid as it falls from the plate and conveying it to a tank to be pumped and used over again.

The action of the Water-douche on highcarbon steel is, as might be expected, to produce intense hardness. As the carbon is lower the hardening becomes less marked;

but an appreciable hardening or stiffening effect is produced with steels containing as little as two-tenths of one per cent. of carbon. In such a case the effect of the treatment resembles that obtained by hardening a steel of somewhat higher carbon in oil at, say, 1,600o Fahrenheit, and then annealing at, say, 900O Fahrenheit. The Wet air has a milder action (on large masses,) about that of oil-hardening at 1,800o Fahrenheit and annealing at 1,200O Fahrenheit. Dry air, especially hot dry air, has the mildest effect of all; but the uniform distribution of the cooling action peculiar to this invention always results in improving the steel.

By the treatment above set forth I am enabled to readily produce tempered and hardened plates of the right shape, notwithstanding the warping caused by the process of hardening or tempering as usually carried out, and should any of the plates fail to fit it will be found that they are so little out of their designed shaped that they can be readily fitted by grinding.

I cla-im as my invention- I. The herein-described method for the manufacture of armor-plates, which consists in making and machining the plate, plugging the holes and keyways, protecting the edges and corners by shoes or guards, heating the plate to a hardening heat, and then subjecting it to sprays of a chilling-fluid acting downwardly upon its front or shot-receiving side.

2. The herein -described method for the manufacture of armor-plates, which consists in making and finishing the plate to a shape indicated by a false templet different from the designer-s templet, heating the plate to a hardening heat, and subjecting the steel or shot-receiving side of the plate to sprays of a chilling fluid to harden said shot-receiving side and bend the plate to the form required for use.

3. The herein described method for the manufacture of armor-plates, which consists in forming a plate to a shape indicated by a false templet different from the designers templet, heating the plate to a hardening heat, and simultaneously subjecting both the shot-receiving side and the rear side of the plate to sprays of a chilling fluid to harden and bend it to the form required for use.

Clerks 15o Messrs. Burdekm ci@ C'o., Solrs.,

Shejjeld, England.

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